The Message Router is for customers of the Retain for Mobile module. The Message Router connects with mobile devices to handle SMS message log forwarding, BBMP device configuration. It typically would sit inside a DMZ.
443 (TCP) Requires both incoming from and outgoing access to the Internet as well as incoming from and outgoing access to the Retain Server.
111/2049 (UDP / TCP) for NFS Client services. (Only required if not using REST) Requires outgoing access if the Worker is not on the Message Router server so that it can place the logs on the Worker's server. Samba can be used, but NFS seems to be more reliable.
It is up to the customer to do this research to get NFS services to work properly.